Do I have a partially blown head gasket??

[Ripple]

I recently took my 2004 Pathfinder LE with 188K miles on a 3800 mile road trip with a couple of buddies. After the first few days the pathy started run hotter than normal and we noticed the engine was losing a significant amount of oil and coolant had been spraying out of the plastic cap of the overflow tank. We were in a pinch being so far away from home so we limited our driving significantly and made sure to top off oil and coolant everyday. After further inspection I also noticed oil sitting on the surface of my overflow tank. My first thought was the headgasket leaking oil into the cooling system causing it to overpressurize and spray out. However, the car was running completely fine as long as fluids were closely monitored and I don't have any indication of "milkshake" in my oil cap. There is also no white smoke coming from my exhaust. After more research the oil cooler looked like a possible suspect. I do have a slight oil leak there visible from the underside of the car, so I opted for a bottle of blue devil oil stop leak. In the following day this greatly decreased my oil consumption and seemed to keep more oil from getting into my coolant system, but I was still rapidly losing coolant. I did make it back home without any overheating but I wanted to get outside opinions since I have never experienced this before. Is it possible my head gasket is still leaking exhaust fumes into my coolant and causing excess pressure? Are there any tests I could do that anyone recommends? Thanks.

[CamperDan]

14 hours ago, Ripple said:

I recently took my 2004 Pathfinder LE with 188K miles on a 3800 mile road trip with a couple of buddies. After the first few days the pathy started run hotter than normal and we noticed the engine was losing a significant amount of oil and coolant had been spraying out of the plastic cap of the overflow tank. We were in a pinch being so far away from home so we limited our driving significantly and made sure to top off oil and coolant everyday. After further inspection I also noticed oil sitting on the surface of my overflow tank. My first thought was the headgasket leaking oil into the cooling system causing it to overpressurize and spray out. However, the car was running completely fine as long as fluids were closely monitored and I don't have any indication of "milkshake" in my oil cap. There is also no white smoke coming from my exhaust. After more research the oil cooler looked like a possible suspect. I do have a slight oil leak there visible from the underside of the car, so I opted for a bottle of blue devil oil stop leak. In the following day this greatly decreased my oil consumption and seemed to keep more oil from getting into my coolant system, but I was still rapidly losing coolant. I did make it back home without any overheating but I wanted to get outside opinions since I have never experienced this before. Is it possible my head gasket is still leaking exhaust fumes into my coolant and causing excess pressure? Are there any tests I could do that anyone recommends? Thanks.

Sorry to hear about the recent issues you have been having with your R50, you can complete a head gasket combustion leak test. Here's a link to were you can get said leak test kit. https://amzn.to/3Rf56Jc

 

It is straight forward and very easy to complete this test with the use of this test kit. I sincerely hope it's not a blown head gasket. Oh you can also try bleeding air from your cooling system via the bleed port on the backside of your engine, it will be covered by a rubber cap. Just make sure you are doing this when the engine is cold and with it off Good luck.

 

Chris. 

[Ripple]

Thanks for the feedback! I will go ahead and order that combustion leak test and go from there. I have watched a good chunk of your youtube videos and have found them extremely helpful when performing maintenance or modifying my R50. 

[CamperDan]

8 hours ago, Ripple said:

Thanks for the feedback! I will go ahead and order that combustion leak test and go from there. I have watched a good chunk of your youtube videos and have found them extremely helpful when performing maintenance or modifying my R50. 

You are very welcome, I'm always happy to help, and thank you again for all of your views and support. I'm also pleased to hear that you have found my YouTube videos helpful.

 

Chris.

[Slartibartfast]

Oil in the coolant is never a good sign. Bizarre that the blue schmoo in the coolant would slow the oil loss, though.

 

I diagnosed a head gasket on a neighbor's Toyota last year. No clouds, plugs looked OK, no obvious misfire, though he said it felt down on power. I got an occasional bubble out of the radiator with the cap off, but wasn't sure I'd bled it right when I'd refilled it, so I wasn't gonna call it just from that. The smoking gun was when I put compressed air to one of the cylinders (like you would with a leakdown tester, except I didn't have one, so I just used the air nozzle) and the air just boiled out of the radiator.

 

The combustion leak test should tell you the same thing.

 

A failed cooler could explain the oil in the coolant, but I don't think it would explain where the coolant is going.

[Ripple]

I ran the test and unfortunately I do have exhaust gases circulating through my cooling system. I know changing the head gaskets on the VQ35DE is a nightmare but I think I'm up for the task. I've been able to pull up the factory service manual but I was wondering if anyone had access to any other resources online that they think would be helpful. I still have a good bit of research to do but I was also wondering if there is anything else I should replace while I tear the engine down. Thanks.

Edited June 9, 2024 by Ripple

[Slartibartfast]

From what I've read about what goes wrong on VQs, I'd loctite the power valve screws while it's torn down. IIRC there's a coolant pipe between the heads at the back, with a second thermostat, that's a pain to access normally. Same story with the PCV valve. Valve cover gaskets probably need doing. And you already know the cooler is leaking.

 

The service manual is likely your best bet, but the power valve screws writeup may help for the intake disassembly. Nissan used (and still uses!) the VQ in a few other platforms, so you might find a writeup or even a video for a more popular model using the same(ish) equipment. I wouldn't use this in place of the manual, but it might show some work-arounds for special tools, or other things that you should check while you're in there.

[Ripple]

I have been through the intake manifold already and replaced the pcv valve as well as adding loctite to the power valve screws so I go that checked off the list! Life has been busy and progress has been slow but I am finally ready to remove the upper oil pan and timing cover in order to get to the heads. I borrowed a hoist from a friend but the service manual says to install engine slingers which I do not own. I was wondering if there was any known alternative to get the hoist hooked up to the engine. I'm trying to have everything finished up for a trip in a few weeks so any help would be greatly appreciated. Thanks.